Tank container



FIG. 1 is a perspective view of a tank container embodying the design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is bottom plan view thereof;

FIG. 5 is a front end view thereof; and,

FIG. 6 is a rear end view thereof. 

The ornamental design for a tank container, as shown and described. 